This proposal outlines a novel and efficient strategy for the total synthesis of a wide range of structurally diverse and biologically active natural products. Many of the compounds to be studied exhibit significant antitumor, schistosomicidal and antimicrobial activity and most of the target molecules possess a seven-membered carbocycle as a prominent structural feature. The synthetic studies are based principally on exploring the unusual chemistry of the troponoids and application of this chemistry to the construction of hydroazulenic intermediates. The principal objectives include the elaboration of a number of complex compounds in the active, natural antipodal form. Mechanistic implications of this chemistry will also be explored.